PHP randomly generated random number of letter combination examples _php tips

In many systems environment everyone will use the letter combination of various coding, the following recommendations are very useful PHP code.

$num are grouped by several letters.

$s letters contain capitalization and can be leveled in uppercase or lowercase.

Copy Code code as follows:

function Makecode ($num =4) {
$re = ";
$s = ' abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz ';
while (strlen ($re) < $num) {
$re. = $s [rand (0, strlen ($s)-1)]; Random generation of a character from $s
}
return $re;
}